PT-141

PT-141 was originally developed by Palatin Technologies as a nasal spray for erectile dysfunction and later repurposed for female hypoactive sexual desire disorder (HSDD). Phase 3 trials demonstrated modest efficacy for HSDD, leading to FDA approval in 2019 under the brand name Vyleesi as a subcutaneous autoinjector. The drug met primary endpoints for increased satisfying sexual events and reduced distress, though effect sizes were small and dropout rates in trials were significant. Evidence for erectile dysfunction comes primarily from early Phase 2 studies; development for ED was discontinued in favor of the HSDD indication. Long-term safety data remains limited, and the mechanism by which central melanocortin activation translates to increased sexual desire is not fully elucidated.